Pull-set mechanism



Dec. 1, 1959 D.'MORR|$0N PULL-SET MECHANISM Filed July 19, 1957 United States Patent PULL-SET MECHANISM David Morrison, Athens, Ga., assignor to General Time Corporation, New York, N.Y., a corporation of Delaware ApplicationJuly 19, 1957, Serial No. 672,944

9' Claims. (CI. 58-80) The present invention relates to clock setting devices and more particularly to a pull-set mechanism for adjusting the position of the hands of a clock.

Clocks are quite commonly provided with pull-set mechanisms which include a grasping knob that may be pulled, for drawing a setting gear into engagement with the gear train driving the minute and hour hands of the clock, and then turned to rotate the hands to a desired position. Heretofore, the design and manufacture of an economical mechanism of this type has presented a number of problems. Primarily, problems resulted from the requirement that gears must be journaled in almost exact alinement if they are to be shiftable into and out of meshing engagement, and it has been found difficult to economically provide and maintain exact alinement for the shifting gear in the mechanisms. Also it has been necessary to control the amount of lateral play within close limits to avoid binding or skipping.

It is,therefore, the general aim of the invention to provide a pull-set mechanism having a shiftable setting gear that isflo'atingly mounted, with the mechanism being effective to assure proper operation without precise alinement problems. It is a related object to provide such a. mechanism with a setting gear that is self-centering and resiliently held in proper position when drawn into meshingengagement with a gear in the hand-motion gear train of a clock so that the gears will not bind when setting the clock.

It is also an object to provide a pull-set mechanism which eliminates the possibility of gear tooth damage when the setting gear is drawn into engagement with the of the above type in whichpositive force transmission from the setting gear to the hand-motion gears is assured, although'the gears are self-centering and thus relatively movable.

It is a more detailed object to provide a pull-set mechanism having the above characteristics which is economical to manufacture'since preassembly is possible with the parts merely being slipped into final position and without adherence to close tolerances. It is a related detailed object to utilize a single resilient clip of novel design bothforurging the setting gear into normal disengaged position'and for resiliently holding that gear in proper meshing interengagement when the pull-set mechanism is beingused.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

' Figure 1 is a rear view of a clock with a portion of the-back cover removed showing a pull-set mechanism line 3-3 of Fig. 1 showing the setting gear in its disengaged or rest position.

Fig. 3a is a view similar to Fig. 3 but showing the position of the setting gear after pulling of the shaft.

Fig. 4 is an enlarged fragmentary view of the pull-set mechanism, with the dotted lines showing the same in its setting position.

Fig. 5 is a fragmentary sectional view similar to Figs. 3 and 3a but showing the movement which results from rotating the setting gear shaft.

Fig. 6 is a fragmentary view showing a step in the assembly of the pull-set mechanism of Fig. l.

Fig. 7 is a fragmentary exploded view showing the step of snapping the spring onto the shaft.

While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodi ment. On the contrary, I intend to cover all modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Turning first to Figs. 1 and 2, there is shown a clock mechanism 10 including a front frame plate 11, a set of conventional hands 12, and a hand-motion driving gear train 13. In the illustrated embodiment, the clock is electrically powered, being provided with a synchronous A.-C. motor 15 which is coupled to the gear train 13 and thus effective to rotate the hands 12 in the usual manner.

Surrounding and enclosing the clock mechanisms carried on the frame plate 11 is a decorative bezel or housing 16. The housing 16 also serves to support a back clock cover 1611 and a front lens 16b.

In order to set the clock hands 12, a gear wheel 1'7 is journaled on the frame plate 11 and disposed in meshing engagement with one of the gears making up the handmotion driving gear train 13. It will thus be appreciated that rotational movement of the gear wheel 17 will be imparted to the hands 12, so that the clock 10 may be set by angularly positioning the gear wheel.

In accordance with the present invention, the clock 10 is provided with a novel pull-set mechanism comprising a setting gear which is mounted for' endwise sliding movement into meshing engagement with a gear in the setting train accompanied by lateral camming of the setting gear into a fully seated position. In the present embodiment, a setting gear 20 is fixed to a shaft 21, one end of which extends through, and is journaled in, the lower portion of the clock housing 16 and which carries a knob 22.

For journaling the upper end of the shaft 21 and permitting lateral and endwise shaft movement, a clip 25 is provided having an annular portion 26 which snaps into a peripheral groove 27 formed on the shaft 21 (see Fig. 7).

To achieve a floating mounting of the shaft 21, the clip 25 is provided with stiff yet resilient arms 31, 32 which are received in a bracket 33, the shaft 21 extending through a relatively large central opening 34 in the bracket. It can be seen that the resilience of the arms 31, 32 permits the shaft 21, journaled in the clip 25, to be moved laterally freely within the central bracket opening 34. The parts are so assembled and arranged that the gear 20 is normally supported closely adjacent, but out of contact with, the gear wheel 17. The bracket 33 preferably is defined by a tab formed integrally with, and bent upwardly from, the front frame plate 11.

For the purpose of camming the settinggear 20 into meshing engagement with the gear wheel 17 upon endwise movement of the shaft 21, the stiff resilient arms 31, 32 of the clip 25 are inclined with respect to the sh'aft'2 1 and are passed through a pair of holes or openings 35, 36, respectively, formed in the bracket 33. Under rest conditions the shaft 21 occupies the position shown in Fig. 3 with the setting gear Well clear of the gear 17. It will be apparent that moving the shaft 21 in an endwise direction, that is, in the direction of the arrow in Fig. 2, the inclined arms 31, 32 will be drawn through the openings 35, 36 and will cam the shaft 21 and the gear 20 toward the gear wheel 17 from the position shown in Fig. 3 to that shown in Fig. 3a. The angle at which the arms 31, 32, are disposed with respect to the shaft is selected so that the gear 20 and the gear wheel 17 will come together in meshing engagement as the arms ride through their respective openings.

To resiliently urge the shaft 21 to a rest position with the setting gear 20 out of engagement with the gear wheel 17, the stiff resilient arms 31, 32 are diverged outwardly from one another so that drawing the arms through the openings 35, 36 to cam the setting gear 20 toward the gear wheel 17 will deflect or bow the arms toward one another (see Fig. 4). This bowing deflection of the arms creates a resilient force tending to return the shaft 21 upwardly to a rest position where the arms 31, 32 are straightened and the setting gear 20 is supported out of engagement with the gear wheel 17.

It can be seen from the above that the clip 25 performs three important functions. It is effective for providing a floating support journaling the shaft 21. It also serves through the cooperation of the resilient arms 31, 32 with the openings 35, 36, to resiliently cam the setting gear 20 into engagement with the gear wheel 17 upon endwise movement of the shaft 21. Moreover, the bowing of the arms 31, 32 incident to their being drawn through the openings 35, 36 develops a resilient force tending to restore the shaft 21 and the setting gear 20 to their normal centered, rest positions out of engagement with the gear wheel 17.

In order to further insure that the shaft 21 is centered when in its upraised or disengaged position, a slot 41 is formed in the opening 34 for loosely embracing the shaft.

Further in accordance with the invention, the central opening 34 in the bracket 33 through which the shaft 21 is disposed, is provided with a pair of camming edges positioned to engage the shaft 21 and to urge the same toward the gear wheel 17 incident to the lateral shift of the shaft which occurs during the setting operation. It will be apparent that since the shaft has lateral freedom within the opening 34, rotation of the setting gear tends to cause the same to walk sideways on the teeth of the gear 17 just as though such gear were a stationary rack, the gear 17 being restrained by friction. In the present construction such tendency is resisted by cam edges 42, 43 (Fig. 3) formed on the bracket 33 and arranged in inverted V formation.

In operation, when the setting gear 20 is in meshing engagement with the gear wheel 17 and the shaft 21 is rotated, the floating mounting of the shaft will allow the reactive force developed in rotating the gear wheel to shift the shaft 21 laterally. For example, if the shaft 21 is turned in a clockwise direction, Fig. 5, it will be carried to the right in that figure. The cam edges 42, 43 are positioned so that this lateral shifting will bring the shaft 21 into abutting engagement with one of the cam edges. In Fig. 5, the shift to the right brings the shaft 21 into engagement with the cam edge 43. It can be seen that the reactive force urging the shaft 21 to the right, which may be represented by a vector arrow 46 produces a downwardly directed component of force represented by the arrow 47. The force 47 thus holds the setting gear 20 in meshing engagement with the gear wheel 17 without reliance upon the resilient camming effect of the arms 31, 32. It will be understood that the greater the driving force exerted by rotating the setting gear 20, the greater will be the reactive force 46, and consequently the component 47 will be proportionately increased to positively hold the setting gear and the gear Wheel in meshing engagement.

It is a feature of the invention that the clip 25 and the bracket 33 are formed to permit preassembly of the setting gear 20 and the shaft 21, and quick convenient assembly of the entire pull-set mechanism. The clip 25 is formed of a single, integral, resilient piece of wire with the journaling portion 26 proportioned to be received by the peripheral groove 27 on the shaft 21. Thus, assembling the clip 25 and the shaft 21 merely involves slipping the clip onto the shaft so that it looks into the groove 27 with a detenting action (see Fig. 7). In the preferred embodiment, the central opening 34 in the bracket 33 is sufficiently large to permit the setting gear 20 to be freely passed therethrough. Thus, the gear 20 may be preassembled in fixed relation on the shaft 21,

and the setting gear and shaft can be installed by merely slipping the gear 20 through the central opening 34 and into proper position with respect to the bracket 33 (see Fig. 6).

To permit the resilient arms to be easily disposed within their respective openings 35, 36, each of the openings is provided with an access slot 35a, 36a, respectively. Thus, when the gear and shaft are properly disposed through the central opening 34 of the bracket 33, the arms 31, 32 of the clip 25, which has been snapped onto the shaft 21, are bent forwardly and slipped through the respective slots 35a and 36a to dispose them within their respective openings 35, 36. It will be appreciated that this assembly procedure is simple, rapid, and requires no special skills or tools.

Due to the floating support of the shaft 21, the setting gear 20 is self-centering with respect to the gear wheel 17. This eliminates any possibility of their respective gear teeth binding as the gears are rotated in setting the clock. Furthermore, the resilient camming action provided by the arms 31, 32 in urging the setting gear 20 into meshing engagement with the gear wheel 17, prevents any possibility of tooth damage as the respective teeth come into contact. It will be understood that if the teeth are drawn together in abutting rather than meshing engagement, the arms 31, 32 will simply deflect until the setting gear 20 is rotated slightly to allow the gear teeth to come into full meshing engagement.

To assist in promoting smooth meshing engagement between the teeth of the setting gear 20 and the gear wheel 17, the latter is provided with gear teeth 17a which are inclined with respect to the body of the gear wheel. This configuration avoids any sharply angled portions which would tend to hook the teeth of the setting gear 20 and block smooth engagement with the teeth of the gear wheel.

It should be noted that there are no critical spacings or adjustments between relative parts of the pull-set mech anism disclosed. The setting gear 20, rather than being precisely alined with the gear wheel 17, is floatingly mounted so that it may freely shift with respect to the gear wheel 17. The camming arms 31, 32 are resilient so that their camming angle need not be precisely determined and maintained, it being understood that after the setting gear 20 and the gear wheel come into engagement further endwise movement of the shaft 21 will merely deflect the resilient arms 31, 32.

Furthermore, the camming edges 42, 43 are of sufficient length so that they will be effective despite slight variations in the lateral shifting movements of the shaft 21.

In the above description, and also in the following claims the term pull-set has been used for convenience to describe an arrangement in which endwise force is applied to a setting shaft to mesh the gears prior to turning the setting shaft. It will be understood that the shaft 21 could, if desired, be extended upwardly, terminating in a suitable setting knob in which case the operation would be the Sain QXCcpt that a push would have to be applied to the shaft'rather than a pull. Consequently, the term pull-set"; shall be considered to coverboth directions of appliedendwise force.

Iclairn as my invention: T

1. In a-clock having timeindicating elements and a gear train for driving said elements, a pull-set mechanism for manuallysetting said indicating elements comprising, in combination, a gear wheel journaled in meshing engagement with said gear train, a setting gear fixed to a shaft'and positioned adjacent said gear wheel, means for journaling said shaft while permitting lateral movegear train for driving said elements, a pull-set mechanism for manually setting said indicating elements comprising, in combination, a gear wheel journaled in meshing engagement with said gear train, means defining a slot positioned adjacent said gear wheel, a shaft extending loosely through said slot, a setting gear fixed to said shaft and positioned adjacent said gear wheel, means to resiliently support said shaft within said slot sothat the setting gear is maintained out of engagement with gear wheel, and means for camming the shaft laterally along the slot as an incident to endwise shaft movement so that the setting gear is carried into meshing engagement with the gear wheel to permit the time indicating elements to be positioned by rotating the shaft.

3. In a clock'having time indicating elements and a gear train for driving said elements, a pull-set mechanism for manually setting said indicating elements comprising, in combination, a gear wheel journaled in meshing engagement with said gear train and having teeth in clined with respect to the body of the gear wheel, means defining a slot positioned adjacent said gear wheel, a shaft extending loosely through said slot, a setting gear fixed to said shaft and positioned adjacent said gear wheel, means to resiliently'support said shaft within said slot so that the setting gear is maintained out of engagement with gear wheel, and cam means for resiliently urging the shaft laterally along the slot as an incident to endwise shaft movement so that the setting gear is carried into meshing engagement with the gear wheel to permit the time indicating elements to be positioned by rotating the shaft, said inclined teeth and said resilient cam means being effective for preventing tooth damage when the setting gear and the gear wheel are brought into engagement.

4. In a clock having time indicating hands and a housing enclosing a hand-motion gear train for driving said hands, a pull-set mechanism for manually setting said hands, comprising, in combination, a gear wheel in meshing engagement with said gear train, a setting gear fixed to a shaft, said shaft being journaled at one end through said housing, a manually manipulatable knob fixed to the portion of said shaft outside of the housing, a clip journaling the shaft within said housing, said clip having means for resiliently camming said shaft and setting gear out of engagement with said gear wheel, said means being overcome upon axial shifting of said shaft so that said setting gear is urged into meshing engagement with said gear wheel whereupon rotation of the shaft will then be effective to rotate said gear wheel and position said hands.

5. In a clock having time indicating hands and a housing enclosing a hand-motion gear train for driving said hands, a pull-set mechanism for manually setting said hands, comprising, in combination, a gear wheel in meshing engagement with said gear train, a setting gear fixed to a shaft, said shaft being journaled at one end through said housing, a manually manipulatable knob fixed to the portion of said shaft outside of the housing, a clip journaling the shaft within said housing and having a stiff'resilient arm extendin'g at an inclined angle from said shaft, 'a flange on said housing having an opening to siidably receive said am so that the shaft and setting gear are supported out of engagement with said gear wheel, said inclined arm being effective to resiliently cam said setting gear into meshing engagement with said gear wheel when the arm is drawn through said opening incident to axial movement of said shaft so that rotation of the shaft will then be effective to rotate said gear wheel and position'said hands.

6. In a clock having time indicated elements and a gear train supported on a frame for driving said elements, a pull-set mechanism for manually setting the indicating elements comprising, in combination, a gear wheel journaled to said frame and effective to drive said gear train, a setting gear fixed to a shaft, a clip loosely journaling said shaft, means to prevent relative axial movement between said clip and said shaft, a pair of stiff resilient arms formed on said clip and extended in mutually diverging directions inclined from the axis of said shaft, a flange securedto said frame and having a pair of openings slidably receiving said arms, said openings being positioned so that the setting gear is normally supported out of engagement but adjacent said gear wheel when the resilient arms are not tensioned, and means for axially shifting and rotating said shaft, said inclined arms being resiliently deflected and thus effective to urge said setting gear into meshing engagement with said gear wheel when the shaft is shifted axially and the arms are drawn through their respective supporting openings, said deflection of said arms also creating a resilient force urging the setting gear back to its normal rest position out of engagement with said gear wheel.

7. In a clock having time indicating elements and a gear train supported on the frame for driving said elements, a pull-set mechanism for manually setting the indicating elements comprising, in combination, a gear wheel journaled on said frame and effective to drive said gear train, a setting gear fixed to a shaft, a clip loosely journaling said shaft, means to prevent relative axial movement between said clip and said shaft, a pair of resilient arms formed on said clip and extending in mutually diverging directions inclined from the axis of said shaft, an upstanding flange secured to said frame adjacent the periphery of said gear wheel, said flange having a central opening through which said shaft is extended and a pair of openings slidably receiving said arms, said pair of openings being positioned so that the setting gear is supported out of engagement, but adjacent, said gear wheel when the resilient arms are not tensioned, and means for axially shifting and rotating said shaft, said inclined arms being resiliently deflected and thus effective to urge said setting gear into meshing engagement with said gear wheel when the shaft is shifted axially and the arms are drawn through their respective supporting openings, said central opening having a pair of sloping camming edges positioned for engaging the shaft on either side respectively when the shaft shifts laterally due to the reactive force developed upon being rotated with the setting gear in meshing engagement with the gear wheel, said camming edges being sloped so as to cam the shifting shaft toward the gear wheel and thus create a force holding the setting gear and gear wheel in meshing engagement for positive power transmission.

8. In a clock having time indicating elements and a gear train supported on the frame for driving said elements, a pull-set mechanism for manually setting the indicating elements comprising, in combination, a gear 37 wheel, an upstandingflange secured to said'frame adjacent the periphery of said gear wheel, said flange having a central opening through which said shaft is extended, means for axially shifting and rotating said shaft, and means for resiliently urging said setting gear into meshing engagement with said gear wheel when the shaft is shifted axially, said central opening having a pair of sloping camming edges positioned for engaging the shaft on either side respectively when the shaft shifts laterally due to the reactive force developed upon being rotated with the setting gear in meshing engagement with the gear wheel, said camming edges being sloped so as to cam the shifting shaft toward the gear wheel and thus create a force holding the setting gear and gear wheel in meshing engagement.

9. In a clock' having time indicating elements and a gear train supported on the frame for driving said elements, at pull-set mechanism for manually setting the indicating elements comprising, in combination, a gear wheel journaled on said frame and effective to drive said gear train, a setting gear fixed to a shaft, said shaft having a peripheral groove near said setting gear, a clip resiliently snapped into said groove so as to loosely journal said shaft, a pair of resilient arms formed on said clip and extending in mutually diverging directions inclined from the axis of said shaft, an upstanding flange secured to said frame adjacent the periphery of said gear wheel, said flange having a central opening through which said shaft is extended anda pair of openings slidably receiving said arms, said pair of openings beingpositioned deflected and thus effective to urge said setting gear into meshing engagement with said gear wheel when the shaft is shifted axially and the arms are drawn through their respective supporting openings, said central opening having a pair of sloping camming edges positioned for engaging the shaft on either side respectively when the shaft shifts laterally due to the reactive force developed upon being rotated with the setting gear in meshing engagement with the gear wheel, said camming edges being sloped so as to cam the shifting shaft toward the gear wheel and thus create a'force'holding the setting gear and gear wheel in meshing engagement for positive power transmission, and said central opening being sufficiently large to permit the setting gear and shaft to be passed therethrough in preassembled relation when assembling said mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 

